The function of $\displaystyle cos \pi/6 = $ the cofunction of $\displaystyle sin \pi/6$ or something similar... (forgot how it was worded)
and would something like -2sin(4x)sin(-2x) be the same as 2sin(4x)sin(2x)
Sine and Cosine are Co-functions.
Meaning,
$\displaystyle \sin x=\cos \left( \frac{\pi}{2} -x \right)$
In the same way,
Tangent and Cotangent are cofunctions.
And,
Secant and Cosecant are cofunctions.
You can use this mnemonic to remember the properties of trigonometric cofunctions.
Ah. So the statement "The function of $\displaystyle cos \pi/6 $ Would = the cofunction of $\displaystyle sin \pi/6 $ ? =)Sine and Cosine are Co-functions.
Meaning,
In the same way,
Tangent and Cotangent are cofunctions.
And,
Secant and Cosecant are cofunctions.